GutAlkaLi LR44 Battery Pack of 20 – 1.5V AG13 Batteries for Watches, Hearing Aids, Glucometer, Key Fobs and Small Electronics – Silver Oxide Chemistry Provides Stable Voltage and Long Lifespan: Amazon.co.uk: Electronics
Amazon.com : 6 Pack MAXELL AG13 LR44 A76 357 Alkaline Button Cell Batteries 1.5 Volt Alkaline : Health & Household